Although the Applicant does not wish to be bound by theory, it is believed that a brief, simplified explanation of the mechanism causing a pool cleaner head to move along a surface will assist a reader's understanding of the invention.
A suction kind, automatic pool cleaner includes a pool cleaner head having a suction pad interfacing with a substrate or surface to be cleaned, and a resilient hose interconnecting an inlet through the pad with a suction inlet of a pump for pumping pool water via a suction area at the interface of the pad and the surface to be cleaned, and via the hose to the pump. In the pool cleaner head, downstream of the suction pad inlet and upstream of the hose, there is provided a flow interruption mechanism for cyclically interrupting the flow, fully or partially. Water flowing along the hose has momentum due to mass and flow speed. Thus, when the flow is interrupted, an area of negative pressure is created in the hose and, because of the cyclic nature of the flow interruption, the negative pressure occurrences are presented as negative pressure pulses. At the occurrence of each negative pressure pulse, over pressure externally of the hose causes contraction and thus a shortening of the hose and thus a corresponding, jerking, displacement of the pool cleaner head. Simultaneously with the interruption of flow, suction between the suction pad and the surface being cleaned is temporarily interrupted, thus facilitating displacement. When flow is resumed, the negative pressure pulse is cancelled, pressures are equalized and the hose extends again, while auction between the pad and the surface is reinstated thus preventing or hindering the head from being displaced.